<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_InfoCard
 * @subpackage Zend_InfoCard_Xml_Security
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Exception.php 2794 2007-01-16 01:29:51Z bkarwin $
 * @author     John Coggeshall <john@zend.com>
 */

/**
 * Zend_Loader
 */
require_once 'Zend/Loader.php';

/**
 * A class to create a transform rule set based on XML URIs and then apply those rules
 * in the correct order to a given XML input
 * 
 * @category   Zend
 * @package    Zend_InfoCard
 * @subpackage Zend_InfoCard_Xml_Security
 * @copyright  Copyright (c) 2005-2007 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @author     John Coggeshall <john@zend.com>
 */
class Zend_InfoCard_Xml_Security_Transform 
{
	/**
	 * A list of transforms to apply
	 *
	 * @var array
	 */
	protected $_transformList = array();
	
	/**
	 * Returns the name of the transform class based on a given URI
	 *
	 * @throws Zend_InfoCard_Xml_Security_Exception
	 * @param string $uri The transform URI
	 * @return string The transform implementation class name
	 */
	protected function _findClassbyURI($uri) 
    {
		switch($uri) {
			case 'http://www.w3.org/2000/09/xmldsig#enveloped-signature':
				return 'Zend_InfoCard_Xml_Security_Transform_EnvelopedSignature';
			case 'http://www.w3.org/2001/10/xml-exc-c14n#':
				return 'Zend_InfoCard_Xml_Security_Transform_XmlExcC14N';
			default:
				throw new Zend_InfoCard_Xml_Security_Exception("Unknown or Unsupported Transformation Requested");
		}
	}
	
	/**
	 * Add a Transform URI to the list of transforms to perform
	 *
	 * @param string $uri The Transform URI
	 * @return Zend_InfoCard_Xml_Security_Transform
	 */
	public function addTransform($uri) 
    {
		$class = $this->_findClassbyURI($uri);
		
		$this->_transformList[] = array('uri' => $uri,
		                                'class' => $class);
		return $this;		                                
	}

	/**
	 * Return the list of transforms to perform
	 *
	 * @return array The list of transforms
	 */
	public function getTransformList() 
    {
		return $this->_transformList;
	}
	
	/**
	 * Apply the transforms in the transform list to the input XML document
	 *
	 * @param string $strXmlDocument The input XML
	 * @return string The XML after the transformations have been applied
	 */
	public function applyTransforms($strXmlDocument) 
    {
		foreach($this->_transformList as $transform) {
			Zend_Loader::loadClass($transform['class']);			
			
			$transformer = new $transform['class'];

			// We can't really test this check because it would require logic changes in the component itself
			// @codeCoverageIgnoreStart
			if(!($transformer instanceof Zend_InfoCard_Xml_Security_Transform_Interface)) {
				throw new Zend_InfoCard_Xml_Security_Exception("Transforms must implement the Transform Interface");
			}
			// @codeCoverageIgnoreEnd
			
			$strXmlDocument = $transformer->transform($strXmlDocument);
		}
		
		return $strXmlDocument;
	}
}
